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1948-49 Theatre Catalog, 7th Edition, Page 267 (256)

1948-49 Theatre Catalog, 7th Edition
1948-49 Theatre Catalog
1948-49 Theatre Catalog, 7th Edition, Page 267
Page 267

1948-49 Theatre Catalog, 7th Edition, Page 267

(FIG. la.) Rear seat vision from the first ramp of a large theatre. While 143 feet from the screen the patron's vision tails to encompass the screen.

slight, will prove economical from a grading standpoint. This is particularly so if you can cut into the land approximately two feet at the low point and still obtain drainage.

Grading on a sloped site will prove just as economical as on flat, provided the slope is uniform and not too steep. A variety of conditions may exist and still economical grading costs be realized. The ground can slope toward the screen but preferably at not more than four feet in 100. It may slope away from the screen but preferably at not more than three feet in 100. It may slope from one side of the theatre to the other but preferably at not more than five feet in 100.

These are the conditions necessary to the most economical grading. Many very profitable theatres have been constructed on sites not meeting these specifications. Often the ideal topography is not available, or more often still, better located sites will justify a greater grading expense. This may also be true, of course, of land that is cheap because it is low. Grading cost should be added to land cost in appraising the value of any site. There again the wide experience of such

(FIG. lb.) Rear seat vision from the first ramp of the same large theatre should patron sit on seat edge and lean forward. This just about does it.

men as the Messrs. Smith can be of inestimable help to the builder.

The Grading Problem

The best indoor theatre design provides clear view of the screen from any seat; but most such theatres depend on the ability of the patron to see around an obstruction. Two row spacing and similar seating layouts are only possible because of the freedom of the individual to shift or move.

Visibility is so limited and framed by the windshield of a car, that all sight lines must be kept clear in a drive-in theatre. This means that not only must the occupants of any car be able to see the bottom of the screen over the car ahead, but the car must be so aimed that the entire picture (perhaps 44f X 60') can be encompassed within the windshield, usually 12" to 14" high. Imagine yourself in the rear seat of an automobile looking through the narrow windshield; or better, get into one, and you see how different this is to indoor visibility conditions. (Fig. l.)

The front of the car is elevated for the aiming operation by use of a ramp and the driver can control the angle of

(FIG. g.) Twilight View of the same large theatre illustrated above shows the system of ramps of varying heights and the maxunum viewing angle consistent with patron vision without distortion. Distance from the screen affecting visibility. and maximum acceptable viewing angle, dictate the theatre size.

(FIG. 1:.) Critical vision lines of a drive-in can best be understood from this series. Note the perfect rear seat vision from the second ramp.

the car by the distance he drives up the ramp. It is not enough to just throw up a series of ramps. Each ramp must be related to the preceding one so that patrons parked in that ramp can see the entire screen over the cars ahead (see Hollingshead patent). We must go as high with each succeeding ramp as necessary to accomplish this purpose, but no higher or we increase grading costs and complicate drainage.

The calculation of such a system of ramps is not difhcult, but it involves the use of the correct factors and painstaking thoroughness. Just one system of ramps will not do, however. We must have a large number of systems calculated and ready, and select the one that best fits the topography (Fig. 2). Here again is where the long and varied experience proves useful. Park-In Theatres through its engineering department, furnishes all of its licensees with location and grading plans tailored to their sites. Careful engineering is used to select just the right system of ramps and their fitting to the ground surface to Obtain a minimum of earthwork with adequate drainage.

The least amount of earthwork, therefore, the least amount of earthwork cost is obtained by balancing cuts and fills so that the fills are made by the material obtained from the cuts. Cuts mean that we must cut into the existing ground surface. Drainage must be obtained away from this cut surface. With very fiat tracts this is sometimes difficult, particularly if there are no ditches or drainage pipes available.

If drainage cannot be had from the low point of a theatre it may be necessary to grade the theatre by bringing in fill from the outside. The fill method is expensive, unless adequate material is available at a very low price. Such an increased earthwork can be as great as fourfold in case of an entire fill job.

For drainage purposes, side pitch of the theatre should not be less than 0.4 percent and for purposes of comfortable sitting not more than 4.0 percent. The theatre may be drained to both sides or across the theatre from one side to the other, depending upon the topography of the site and the drainage conditions. In one case, it proved economical to drain from both sides to the center. This requircd a pipe drain with inlets through the center of the theatre. This is unusual.


1948-49 Theatre Catalog, 7th Edition, Page 267